Designing a Mac-to-VGA monitor sync-splitter adapter

[mg.man]

I figured I should move this convo to the main Sync-inator thread...

I looked at the pinout for those 8-bit Apple TTL adapters

Oh, I didn't know such a thing existed? Do you have a link? Or did you mean 'video card' rather than 'adapter'?

But an Apple TTL adapter would also need a different pin mapping for the I-intensity channel at a minimum, plus some analog circuit for mixing TTL-level RGBI down to 0.7v analog level RGB. But you could certainly imagine a different device - the TTL-inator?

Makes sense. IDK what the market would be like - certainly not as large as that for the Sync-inator. I wonder if there's one or a small number of TTL-input CRTs these cards drove? Like I said in the other thread, just thinking out loud since I have at least one NuBUS card, a "clip on" video adapter for a Plus, and - I think? - a similar external video card for an SE PDS slot all with DB9 output. All pretty useless atm.

 

[Phipli]

Something that did ECL for all the old cards would be awesome. I looked into it at one point but the chips that do it easily are no longer made. There is... An Atari community design adapter, I can't remember but I think it used an obsolete chip.

A warning WRT 9 pin outputs - they're not standardised pinout. Worse than that, I swear every one is different.

ECL cards are common for SEs. Sadly.

 

[Phipli]

Home-brew Atari TT ECL VGA Adapter - exxos's Atari, Amiga & retro forum

exxosforum.co.uk

 

[NJRoadfan]

The TenoxVGA adapter handles ECL to VGA: https://github.com/tenox7/tenoxvga

It is available for sale assembled: https://www.legacypixels.com/atari/

 

[Phipli]

The TenoxVGA adapter handles ECL to VGA: https://github.com/tenox7/tenoxvga

It is available for sale assembled: https://www.legacypixels.com/atari/

That's excellent thank you. I'll have a rummage through the design and see what they're using.

 

[mg.man]

The TenoxVGA adapter handles ECL to VGA

Likewise, interesting... sounds like we need to launch a new thread... @Phipli - maybe you should start an ECL-inator thread?

 

[Phipli]

Likewise, interesting... sounds like we need to launch a new thread... @Phipli - maybe you should start an ECL-inator thread?

Ah sorry, I thought you were moving the conversation here.

 

[Phipli]

I figured I should move this convo to the main Sync-inator thread...

Oh, I didn't know such a thing existed? Do you have a link? Or did you mean 'video card' rather than 'adapter'?

Makes sense. IDK what the market would be like - certainly not as large as that for the Sync-inator. I wonder if there's one or a small number of TTL-input CRTs these cards drove? Like I said in the other thread, just thinking out loud since I have at least one NuBUS card, a "clip on" video adapter for a Plus, and - I think? - a similar external video card for an SE PDS slot all with DB9 output. All pretty useless atm.

By the way, I made a spreadsheet for doing calculations for TTL to VGA (resistor selection). But my preference would be to use a transistor so you could drive all three channels without overloading the video card. The spreadsheet is pretty basic but is might save someone else having to do the same again if needed.

 

[mg.man]

I thought you were moving the conversation here.

I suppose the thread Subject is broad enough to cover TTL- and ECL-

 

[Phipli]

With warning, this is just what I sent to someone a while backfrom my phone and might not be correct or my latest version. Verify my work before depending on it.

 

[LaPorta]

Do we post our findings here, or another thread?